The Sharp Zaurus is the name of a series of personal digital assistants (PDAs) made by Sharp Corporation. The Zaurus was the most popular PDA during the 1990s in Japan and was based on a proprietary operating system. The first Sharp PDA to use the Linux operating system was the SL-5000D, running the Qtopia-based Embedix Plus. The Linux Documentation Project considers the Zaurus series to be "true Linux PDAs" because their manufacturers install Linux-based operating systems on them by default.[1] The name derives from the common suffix applied to the names of dinosaurs.